This is great, and doesn't use up as much soy sauce as the traditional Japanese versions of teriyaki. It works great in stir fries where you'll use it to coat veggies, tofu or chicken. My parents were hooked on bottled teriyaki sauces, which often have corn syrup or additives-- I think this is easy enough to make in batch to keep on hand instead of store-bought sauce.
Combine in a saucepan, bring to a boil:
2 C water
1/2 C soy sauce
1/4 C - 1/2 C brown sugar (decide how much based on how sweet you want it)
2 TB agave or maple syrup
few cloves crushed garlic
1 tsp microplane minced ginger root
Meanwhile, in a small bowl, mix up 2 TB cornstarch and 1/4 C cold water. Set aside.
Open a can of crushed pineapple.
Once the sauce pan is boiling, slowly stir in the cornstarch slurry while stirring. Add 1/4 C crushed pineapple, take off heat.
You can keep this sauce in the fridge, which is handy as this makes a lot of sauce!